JPH0635445Y2 - Drum-shaped magnetic core - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement of a drum-shaped magnetic core used for a high-frequency coil or the like. More specifically, a thin resin bobbin having a special shape is fitted on the core of the drum-shaped magnetic core. The present invention relates to a drum-shaped magnetic core capable of improving insulation and preventing damage to a coil wire.

[Prior Art] A ferrite drum type magnetic core in which large-diameter flange portions are provided at both ends of a small-diameter core portion in the center is well known in the art, and a wire rod is wound around the central core portion to form a high-frequency transformer or a high-frequency transformer. Widely used for coils etc.

A conventional drum-shaped magnetic core usually has a structure in which a central winding core portion and flange portions located at both ends are continuously integrated.
Since a drum-shaped magnetic core with such a shape cannot be directly molded with a press molding machine, first form a ferrite cylinder,
Then, the center portion is manufactured by grinding the outer periphery using a coreless grinding device or the like. Due to the shape of the grinding wheel used for grinding, the inner edge of the flange portion of the drum-shaped magnetic core had a substantially right-angled cross section.

The wire rod end of the winding wire applied to the central small-diameter winding core portion is often drawn out as it is, and is entangled with a terminal pin or the like attached to the magnetic core or the base member for soldering connection.

[Problems to be Solved by the Invention] In the conventional drum-shaped magnetic core, the wound wire rod end may come into contact with the corner portion of the inner edge of the flange portion to cause damage or peeling of the insulating coating. was there.

In particular, when a manganese-zinc based material is used as the magnetic core material, its surface resistance is so small that even if the wire material is slightly scratched, a short circuit accident will occur. Manganese-zinc type ferrite has unique electrical characteristics not found in nickel-zinc type ferrites that have been conventionally used in the high frequency range. Becomes

A varnish treatment has been applied to the surface of the magnetic core to improve the electric insulation, but the varnish is difficult to adhere to the corners of the flange, and the insulation treatment becomes incomplete, resulting in the short-circuit accident as described above. Could not be completely prevented.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, and even if a magnetic core of a material having a small surface electric resistance such as manganese-zinc ferrite is used, the insulation failure of the wire does not occur, and the manufacturing is very easy. It is to provide a drum-shaped magnetic core that is easy to play.

[Means for Solving the Problems] In the present invention which can achieve the above objects, a drum-shaped magnetic core is divided into a disk-shaped one-flange-shaped magnetic core and a ring-shaped magnetic core, and a winding core is provided. A thin resin bobbin with a special shape is fitted to the portion to facilitate assembly and improve electrical insulation.

The resin bobbin in the present invention is an integrally molded product made of thin synthetic resin. The size of both flanges should be the same or larger than the flange of the magnetic core. A bending extension is provided outward at the outer peripheral edge of at least one flange portion of the resin bobbin so as to cover at least a part of the magnetic core corner.

The present invention can be applied to magnetic cores of any material, but is particularly effective when a material having a low surface electric resistance such as manganese-zinc ferrite is used.

[Operation] The winding is provided on the resin bobbin, and its end is pulled out along the bending extension of the flange portion of the resin bobbin.
Usually, it is connected by tying it to an external terminal pin or the like by soldering. Even if the magnetic core is made of a material with low surface resistance such as manganese-zinc ferrite, the coil wire is hard to be damaged because the winding part and the part where the winding end is pulled out are covered with the resin bobbin. No defects will occur.

[Embodiment] FIG. 1 is an exploded perspective view showing an embodiment of a drum-shaped magnetic core according to the present invention. This drum-shaped magnetic core is a single-flange magnetic core 14 in which a disk-shaped large-diameter flange portion 12 is continuously and integrally formed at one end of a small-diameter core portion 10, and a special shape fitted to the core portion 10. The resin bobbin 16 and the ring-shaped magnetic core 18 fitted and fixed to the other end of the winding core 10.

The one-flange type magnetic core 14 and the ring type magnetic core 18 are, for example, manganese-zinc based ferrite sintered bodies. Unlike the prior art, the single-flange bobbin 14 and the ring-shaped magnetic core 18 are easily compression-molded into a predetermined final product shape by a press molding machine. Therefore, the outer peripheral grinding step is unnecessary. The resin bobbin 16 is integrally molded with an extremely thin synthetic resin. The outer diameters of the two flange portions 16a are substantially the same as or slightly larger than the outer diameter of the flange portion 12 of the one-flange type magnetic core 14 or the outer diameter of the ring type magnetic core 18. An annular bending extension 16b is integrally formed outward so as to be continuous with the outer peripheral edges of both flange portions 16a, and the bending extension 16b is exactly the inner edge of the flange portion of the one-flange type magnetic core 14. The corners and the edge corners of the ring-shaped magnetic core 18 are covered.

After the resin bobbin 16 is fitted on the winding core portion 10, the ring-shaped magnetic core 18 is fitted and fixed with an adhesive or the like to obtain a drum-shaped magnetic core. The winding may be applied to the resin bobbin 16 in advance, or may be applied after the resin bobbin 16 is fitted and the ring-shaped magnetic core 18 is fitted and fixed.

FIG. 2 is a sectional view showing an example of a winding part using such a drum-shaped magnetic core. In the figure, reference numeral 20 indicates a winding.

In such a drum-shaped magnetic core, terminal pins are usually attached directly to the end surface of the drum-shaped magnetic core, or fixed to a base member having terminal pins, and the wire rod ends of the winding are entangled with the bases of the terminal pins. By adopting a structure in which it is fixed by soldering, the mounting on a printed wiring board or the like becomes easier.

The present invention is not limited to the configuration shown in the above embodiment. In the present invention, the bending extension provided on the outer periphery of the flange portion may be provided on only one side corresponding to the case where the winding terminal is drawn in only one direction. Further, the bent extension portion does not necessarily have to be a circular ring shape, and may be formed partially only in the vicinity of the corner of the magnetic core where the winding end contacts.

[Advantage of the Invention] Since the present invention is configured such that the resin bobbin of the special shape is fitted to the winding core and the winding is applied to the winding core as described above, when the end of the wound wire is pulled out, It is possible to completely avoid direct contact with the corners of the magnetic core, electrical insulation is further improved, and there is no risk of scratching the wire or peeling of the coating, and a magnetic core material with low surface electrical resistance is used. However, there is an excellent effect that insulation failure does not occur and the yield is significantly improved.

In addition, the combination structure of the one-flange type magnetic core and the ring type magnetic core as in the present invention enables direct compression molding into a final product shape by a press molding machine, which eliminates the need for post-processing as in the prior art and has the advantage of improving productivity. There is also.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing an embodiment of a drum-shaped magnetic core according to the present invention, and FIG. 2 is a sectional view showing a state of use after assembly thereof. 10 ... winding core part, 12 ... flange part, 14 ... single flange type magnetic core,
16 ... Resin bobbin, 16a ... Flange part, 16b ... Bend extension part, 18 ... Ring type core.

Claims (2)

[Scope of utility model registration request] 1. A one-flange type magnetic core having a disk-shaped flange portion formed at one end of a winding core portion, a resin bobbin fitted to the winding core portion, and fixedly fitted to the other end of the winding core portion. The resin bobbin is a thin-walled synthetic resin integrally molded product, and the outer diameters of both flange portions are equal to or greater than the outer diameter of the flange portion of the one-flange core and the ring. A drum-shaped magnetic core having a size equal to or larger than the outer diameter of the shaped magnetic core, and further provided with a bent extension continuously outwardly on the outer periphery of at least one flange portion of the resin bobbin so as to cover the corner portion of the magnetic core. 2. A drum type magnetic core according to claim 1, wherein the magnetic core is made of manganese-zinc ferrite.